Fluency can be defined in terms of intelligibility and effectiveness. For learners of English as a foreign language, fluency includes some degree of accuracy in phonological, syntactic, and semantic terms. It is a quality of speech that is produced in novel situations where what is said and how it is said cannot be predicted. To clarify the factors involved in the concept of fluency and to specify the kind of proficiency testing that would evaluate learners' fluency, a series of experiments were carried out. Ten adult non-native speakers of English were asked to describe the action in a comic strip. They were rated in two ways: (1) native speaker's subjective evaluation of the non-natives' fluency, and (2) non-native speakers' rate of speech and hesitation phenomena. A second experiment attempted to clarify the meaning of the term "non-native pauses." A comparison was made of descriptions of the same comic strip that were made by ten native speakers of English with the descriptions made by the non-native speakers. Non-native speakers were found to have more and longer hesitation pauses than native speakers. Also, the distribution was different. With regard to proficiency testing, the study points to the need for a workable alternative to ratings based on native speakers' intuition. (AMH)